1. Field of the Invention
This invention relates to method and apparatus for treating trees by injecting a chemical solution into frills circumferentially spaced around a tree. This invention relates particularly to method and apparatus for chemically inducing the formation of lightwood, rich in oleoresin content, in growing pine trees.
2. Description of the Prior Art
It is known to chemically induce deposition of oleoresin in a living conifer such as, for example, a slash pine by preparing a treatment site on the hole thereof and subsequently applying thereto an aqueous solution of a treating chemical such as a substituted bipyridylium salt. The oleoresins are extracted after the trees are harvested and the naval stores products are produced from the extract. See U.S. Pat. No. 3,839,823 of Oct. 8, 1974, reference to which is hereby made.
Sapwood of a conifer has long vertical cells, called tracheids, in which sap moves up the bole. These vertical cells are crossed at right angles by ray cells. Ray cells are shorter than vertical cells and are used for conveying food across the conifer to where it is needed. Treatment sites are prepared so that when a solution of treating chemical is applied, it will make contact with both the vertical cells and with the ray cells.
Heretofore, treatment sites have been prepared by removing a small section of bark to expose sapwood; or by making an axe cut deep enough to expose sapwood; or by boring a small downwardly sloping hole into the sapwood. Application of solution of treating chemical to the above treatment sites is made by any convenient means, such, for example, as by use of a sprayer or a brush. With regard to the treatment site prepared by boring a downwardly sloping hole into the sapwood, the solution is applied by pouring it into the hole.
Another method of treatment site preparation involves providing on the sapwood of a living conifer anywhere from ground level to a height of about 10 ft. above ground level at least one elongated, downwardly sloping hole and subsequently inserting into the hole an absorbent fibrous material for receipt of a treating chemical. The treating chemical will usually be applied in the form of a solution thereof in a suitable solvent, water preferably. The absorbent fibrous material functions as a wick and provides for movement of the solution of treating chemical into the conifer. If desired, the treating chemical, alone or in solution, can be applied to the absorbent fibrous material prior to insertion of the fibrous material into the prepared hole. This method of treatment site preparation is disclosed in U.S. Pat. No. 3,971,159 of July 27, 1976, reference to which is hereby made.
Numerous blades are disclosed in the prior art for wounding trees. A blade is disclosed in U.S. Pat. No. 2,927,401 which has a convex-concave cross-section, a fantail-shaped cutting edge, i.e., convex, and provisions for ejectment of liquid from the concave surface in treating trees. The narrow frill made by this blade, causes some of the treating liquid to flow out of the frill and onto the bark of the tree, that portion flowing out of the frill thereby not contacting the sapwood to provide beneficial treatment. This narrow frill is made because the fantail-shaped cutting edge, in operation, slides down between the inner and outer bark and the inner tree, making a narrow wound which is deeper in the center. The narrow frill, combined with overflow of the treating solution down the bar, lowers the efficiency of any treatment program.